What could happen if someone refused to answer questions asked by the house un-American activities committee

The House Un-American Activities Committee (HUAC) was created in 1938 to ... of the war did not suit the political mood of a nation that was largely in favor of FDR's ... to subpoena witness and hold people in contempt of Congress, HUAC often ... "red" if they refused to comply or hesitated in answering committee questions.

Answer: They could be blacklisted. - Apex!